clear;clc
ts=1:45;y=1:45;n=1;
syms a
for  i=1/180:1/180:45/180
tr=4*int(1/sqrt(1-(sin(a/2)*sin(a))^2),a,0,i);
y(n)=tr-2*pi;
ts(n)=tr;
n=n+1;
end
errorbar(1:1:45,ts,y)
xlabel('角度/度');
ylabel('误差/s');